The T helper cells (Th cells) are a type of T cell that play an important role in the immune system, particularly in the adaptive immune system. They help the activity of other immune cells by releasing T cell cytokines.These cells help suppress or regulate immune responses.hey are essential in B cell antibody class switching, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages. Mature T h cells express the surface protein CD4 and are referred to as CD4+ T cells.
Bring the water to a boil over medium-high heat, then turn the heat down and cover the pot with its lid. Simmer the beef for three to five hours, or until tender.Take the temperature of your beef before you stop cooking it -- the meat should reach an internal temperature of 160 degrees Fahrenheit.immer the beef for three to five hours, or until tender. Take the temperature of your beef before you stop cooking it -- the meat should reach an internal temperature of 160 degrees Fahrenheit.
A beef roast cooked to medium-rare should have an internal temperature of 145Â°F - 150ÂºF after the resting period, and a roast cooked to medium should have an internal temperature of 150Â°F to 160ÂºF. (See the note below). See Beef Doneness for more information on proper cooking temperatures.enerally, the roasting time may range from 15 to 30 minutes per pound. The 2Â½ pound, bottom round roast pictured on the right, required 55 minutes cooking time to reach the desired doneness, which in this case is medium rare to medium.